DEVICE_IDS(9) MidnightBSD Kernel Developer’s Manual DEVICE_IDS(9)

NAME

device_ids, major, minor, umajor, uminor — calculate device ids

SYNOPSIS

#include <sys/types.h>
#include <sys/systm.h>

int

major(struct cdev *dev);

int

minor(struct cdev *dev);

int

umajor(dev_t id);

int

uminor(dev_t id);

DESCRIPTION

The device_ids family of functions take either the raw device ID, id, or a pointer to the device structure, dev, and return the integer value that is the major or minor device ID as requested.

The actual major and minor device IDs are values masked from of the raw device ID. For details on the actual calculations used to determine the major or minor IDs see the actual source in kern_conf.c.

RETURN VALUES

An integer greater than zero and less than NUMCDEVSW. major() and minor() will return NODEV if the device is invalid.

AUTHORS

This manual page was written by Chad David 〈davidc@acns.ab.ca〉.

MidnightBSD 0.3 June 22, 2004 MidnightBSD 0.3